[4.2.y-ckt stable] Patch "tipc: fix connection abort during subscription cancel" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    tipc: fix connection abort during subscription cancel

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From d40703ddb7ccbc56b3e8b213fdc1f873d21dbd74 Mon Sep 17 00:00:00 2001
From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan at ericsson.com>
Date: Wed, 27 Jan 2016 11:35:59 +0100
Subject: tipc: fix connection abort during subscription cancel

[ Upstream commit 4d5cfcba2f6ec494d8810b9e3c0a7b06255c8067 ]

In 'commit 7fe8097cef5f ("tipc: fix nullpointer bug when subscribing
to events")', we terminate the connection if the subscription
creation fails.
In the same commit, the subscription creation result was based on
the value of the subscription pointer (set in the function) instead
of the return code.

Unfortunately, the same function tipc_subscrp_create() handles
subscription cancel request. For a subscription cancellation request,
the subscription pointer cannot be set. Thus if a subscriber has
several subscriptions and cancels any of them, the connection is
terminated.

In this commit, we terminate the connection based on the return value
of tipc_subscrp_create().
Fixes: commit 7fe8097cef5f ("tipc: fix nullpointer bug when subscribing to events")

Reviewed-by:  Jon Maloy <jon.maloy at ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan at ericsson.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/tipc/subscr.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
index 350cca3..69ee2ee 100644
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -289,15 +289,14 @@ static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 				struct sockaddr_tipc *addr, void *usr_data,
 				void *buf, size_t len)
 {
-	struct tipc_subscriber *subscriber = usr_data;
+	struct tipc_subscriber *subscrb = usr_data;
 	struct tipc_subscription *sub = NULL;
 	struct tipc_net *tn = net_generic(net, tipc_net_id);

-	tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscriber, &sub);
-	if (sub)
-		tipc_nametbl_subscribe(sub);
-	else
-		tipc_conn_terminate(tn->topsrv, subscriber->conid);
+	if (tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscrb, &sub))
+		return tipc_conn_terminate(tn->topsrv, subscrb->conid);
+
+	tipc_nametbl_subscribe(sub);
 }

 /* Handle one request to establish a new subscriber */
--
2.7.0